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 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.management.openmbean;

// java import
//

import java.util.Set;
import javax.management.Descriptor;
import javax.management.DescriptorRead;  // for Javadoc
import javax.management.ImmutableDescriptor;
import javax.management.MBeanParameterInfo;

// OpenMBeanAttributeInfoSupport and this class are very similar
// but can't easily be refactored because there's no multiple inheritance.
// The best we can do for refactoring is to put a bunch of static methods
// in OpenMBeanAttributeInfoSupport and import them here.
import static javax.management.openmbean.OpenMBeanAttributeInfoSupport.*;

/**
 * Describes a parameter used in one or more operations or
 * constructors of an open MBean.
 *
 * @since 1.5
 */
public class OpenMBeanParameterInfoSupport
    extends MBeanParameterInfo
    implements OpenMBeanParameterInfo {

  /* Serial version */
  static final long serialVersionUID = -7235016873758443122L;

  /**
   * @serial The open mbean parameter's <i>open type</i>
   */
  private OpenType<?> openType;

  /**
   * @serial The open mbean parameter's default value
   */
  private Object defaultValue = null;

  /**
   * @serial The open mbean parameter's legal values. This {@link Set} is unmodifiable
   */
  private Set<?> legalValues = null;  // to be constructed unmodifiable

  /**
   * @serial The open mbean parameter's min value
   */
  private Comparable<?> minValue = null;

  /**
   * @serial The open mbean parameter's max value
   */
  private Comparable<?> maxValue = null;


  // As this instance is immutable, these two values need only
  // be calculated once.
  private transient Integer myHashCode = null;        // As this instance is immutable, these two values
  private transient String myToString = null;        // need only be calculated once.


  /**
   * Constructs an {@code OpenMBeanParameterInfoSupport} instance,
   * which describes the parameter used in one or more operations or
   * constructors of a class of open MBeans, with the specified
   * {@code name}, {@code openType} and {@code description}.
   *
   * @param name cannot be a null or empty string.
   * @param description cannot be a null or empty string.
   * @param openType cannot be null.
   * @throws IllegalArgumentException if {@code name} or {@code description} are null or empty
   * string, or {@code openType} is null.
   */
  public OpenMBeanParameterInfoSupport(String name,
      String description,
      OpenType<?> openType) {
    this(name, description, openType, (Descriptor) null);
  }

  /**
   * Constructs an {@code OpenMBeanParameterInfoSupport} instance,
   * which describes the parameter used in one or more operations or
   * constructors of a class of open MBeans, with the specified
   * {@code name}, {@code openType}, {@code description},
   * and {@code descriptor}.
   *
   * <p>The {@code descriptor} can contain entries that will define
   * the values returned by certain methods of this class, as
   * explained in the <a href="package-summary.html#constraints">
   * package description</a>.
   *
   * @param name cannot be a null or empty string.
   * @param description cannot be a null or empty string.
   * @param openType cannot be null.
   * @param descriptor The descriptor for the parameter.  This may be null which is equivalent to an
   * empty descriptor.
   * @throws IllegalArgumentException if {@code name} or {@code description} are null or empty
   * string, or {@code openType} is null, or the descriptor entries are invalid as described in the
   * <a href="package-summary.html#constraints">package description</a>.
   * @since 1.6
   */
  public OpenMBeanParameterInfoSupport(String name,
      String description,
      OpenType<?> openType,
      Descriptor descriptor) {

    // Construct parent's state
    //
    super(name,
        (openType == null) ? null : openType.getClassName(),
        description,
        ImmutableDescriptor.union(descriptor, (openType == null) ? null :
            openType.getDescriptor()));

    // Initialize this instance's specific state
    //
    this.openType = openType;

    descriptor = getDescriptor();  // replace null by empty
    this.defaultValue = valueFrom(descriptor, "defaultValue", openType);
    this.legalValues = valuesFrom(descriptor, "legalValues", openType);
    this.minValue = comparableValueFrom(descriptor, "minValue", openType);
    this.maxValue = comparableValueFrom(descriptor, "maxValue", openType);

    try {
      check(this);
    } catch (OpenDataException e) {
      throw new IllegalArgumentException(e.getMessage(), e);
    }
  }


  /**
   * Constructs an {@code OpenMBeanParameterInfoSupport} instance,
   * which describes the parameter used in one or more operations or
   * constructors of a class of open MBeans, with the specified
   * {@code name}, {@code openType}, {@code description} and {@code
   * defaultValue}.
   *
   * @param name cannot be a null or empty string.
   * @param description cannot be a null or empty string.
   * @param openType cannot be null.
   * @param defaultValue must be a valid value for the {@code openType} specified for this
   * parameter; default value not supported for {@code ArrayType} and {@code TabularType}; can be
   * null, in which case it means that no default value is set.
   * @param <T> allows the compiler to check that the {@code defaultValue}, if non-null, has the
   * correct Java type for the given {@code openType}.
   * @throws IllegalArgumentException if {@code name} or {@code description} are null or empty
   * string, or {@code openType} is null.
   * @throws OpenDataException if {@code defaultValue} is not a valid value for the specified {@code
   * openType}, or {@code defaultValue} is non null and {@code openType} is an {@code ArrayType} or
   * a {@code TabularType}.
   */
  public <T> OpenMBeanParameterInfoSupport(String name,
      String description,
      OpenType<T> openType,
      T defaultValue)
      throws OpenDataException {
    this(name, description, openType, defaultValue, (T[]) null);
  }

  /**
   * <p>Constructs an {@code OpenMBeanParameterInfoSupport} instance,
   * which describes the parameter used in one or more operations or
   * constructors of a class of open MBeans, with the specified
   * {@code name}, {@code openType}, {@code description}, {@code
   * defaultValue} and {@code legalValues}.</p>
   *
   * <p>The contents of {@code legalValues} are copied, so subsequent
   * modifications of the array referenced by {@code legalValues}
   * have no impact on this {@code OpenMBeanParameterInfoSupport}
   * instance.</p>
   *
   * @param name cannot be a null or empty string.
   * @param description cannot be a null or empty string.
   * @param openType cannot be null.
   * @param defaultValue must be a valid value for the {@code openType} specified for this
   * parameter; default value not supported for {@code ArrayType} and {@code TabularType}; can be
   * null, in which case it means that no default value is set.
   * @param legalValues each contained value must be valid for the {@code openType} specified for
   * this parameter; legal values not supported for {@code ArrayType} and {@code TabularType}; can
   * be null or empty.
   * @param <T> allows the compiler to check that the {@code defaultValue} and {@code legalValues},
   * if non-null, have the correct Java type for the given {@code openType}.
   * @throws IllegalArgumentException if {@code name} or {@code description} are null or empty
   * string, or {@code openType} is null.
   * @throws OpenDataException if {@code defaultValue} is not a valid value for the specified {@code
   * openType}, or one value in {@code legalValues} is not valid for the specified {@code openType},
   * or {@code defaultValue} is non null and {@code openType} is an {@code ArrayType} or a {@code
   * TabularType}, or {@code legalValues} is non null and non empty and {@code openType} is an
   * {@code ArrayType} or a {@code TabularType}, or {@code legalValues} is non null and non empty
   * and {@code defaultValue} is not contained in {@code legalValues}.
   */
  public <T> OpenMBeanParameterInfoSupport(String name,
      String description,
      OpenType<T> openType,
      T defaultValue,
      T[] legalValues)
      throws OpenDataException {
    this(name, description, openType,
        defaultValue, legalValues, null, null);
  }


  /**
   * Constructs an {@code OpenMBeanParameterInfoSupport} instance,
   * which describes the parameter used in one or more operations or
   * constructors of a class of open MBeans, with the specified
   * {@code name}, {@code openType}, {@code description}, {@code
   * defaultValue}, {@code minValue} and {@code maxValue}.
   *
   * It is possible to specify minimal and maximal values only for
   * an open type whose values are {@code Comparable}.
   *
   * @param name cannot be a null or empty string.
   * @param description cannot be a null or empty string.
   * @param openType cannot be null.
   * @param defaultValue must be a valid value for the {@code openType} specified for this
   * parameter; default value not supported for {@code ArrayType} and {@code TabularType}; can be
   * null, in which case it means that no default value is set.
   * @param minValue must be valid for the {@code openType} specified for this parameter; can be
   * null, in which case it means that no minimal value is set.
   * @param maxValue must be valid for the {@code openType} specified for this parameter; can be
   * null, in which case it means that no maximal value is set.
   * @param <T> allows the compiler to check that the {@code defaultValue}, {@code minValue}, and
   * {@code maxValue}, if non-null, have the correct Java type for the given {@code openType}.
   * @throws IllegalArgumentException if {@code name} or {@code description} are null or empty
   * string, or {@code openType} is null.
   * @throws OpenDataException if {@code defaultValue}, {@code minValue} or {@code maxValue} is not
   * a valid value for the specified {@code openType}, or {@code defaultValue} is non null and
   * {@code openType} is an {@code ArrayType} or a {@code TabularType}, or both {@code minValue} and
   * {@code maxValue} are non-null and {@code minValue.compareTo(maxValue) > 0} is {@code true}, or
   * both {@code defaultValue} and {@code minValue} are non-null and {@code
   * minValue.compareTo(defaultValue) > 0} is {@code true}, or both {@code defaultValue} and {@code
   * maxValue} are non-null and {@code defaultValue.compareTo(maxValue) > 0} is {@code true}.
   */
  public <T> OpenMBeanParameterInfoSupport(String name,
      String description,
      OpenType<T> openType,
      T defaultValue,
      Comparable<T> minValue,
      Comparable<T> maxValue)
      throws OpenDataException {
    this(name, description, openType,
        defaultValue, null, minValue, maxValue);
  }

  private <T> OpenMBeanParameterInfoSupport(String name,
      String description,
      OpenType<T> openType,
      T defaultValue,
      T[] legalValues,
      Comparable<T> minValue,
      Comparable<T> maxValue)
      throws OpenDataException {
    super(name,
        (openType == null) ? null : openType.getClassName(),
        description,
        makeDescriptor(openType,
            defaultValue, legalValues, minValue, maxValue));

    this.openType = openType;

    Descriptor d = getDescriptor();
    this.defaultValue = defaultValue;
    this.minValue = minValue;
    this.maxValue = maxValue;
    // We already converted the array into an unmodifiable Set
    // in the descriptor.
    this.legalValues = (Set<?>) d.getFieldValue("legalValues");

    check(this);
  }

  /**
   * An object serialized in a version of the API before Descriptors were
   * added to this class will have an empty or null Descriptor.
   * For consistency with our
   * behavior in this version, we must replace the object with one
   * where the Descriptors reflect the same values of openType, defaultValue,
   * etc.
   **/
  private Object readResolve() {
    if (getDescriptor().getFieldNames().length == 0) {
      // This noise allows us to avoid "unchecked" warnings without
      // having to suppress them explicitly.
      OpenType<Object> xopenType = cast(openType);
      Set<Object> xlegalValues = cast(legalValues);
      Comparable<Object> xminValue = cast(minValue);
      Comparable<Object> xmaxValue = cast(maxValue);
      return new OpenMBeanParameterInfoSupport(
          name, description, openType,
          makeDescriptor(xopenType, defaultValue, xlegalValues,
              xminValue, xmaxValue));
    } else {
      return this;
    }
  }

  /**
   * Returns the open type for the values of the parameter described
   * by this {@code OpenMBeanParameterInfoSupport} instance.
   */
  public OpenType<?> getOpenType() {
    return openType;
  }

  /**
   * Returns the default value for the parameter described by this
   * {@code OpenMBeanParameterInfoSupport} instance, if specified,
   * or {@code null} otherwise.
   */
  public Object getDefaultValue() {

    // Special case for ArrayType and TabularType
    // [JF] TODO: clone it so that it cannot be altered,
    // [JF] TODO: if we decide to support defaultValue as an array itself.
    // [JF] As of today (oct 2000) it is not supported so
    // defaultValue is null for arrays. Nothing to do.

    return defaultValue;
  }

  /**
   * Returns an unmodifiable Set of legal values for the parameter
   * described by this {@code OpenMBeanParameterInfoSupport}
   * instance, if specified, or {@code null} otherwise.
   */
  public Set<?> getLegalValues() {

    // Special case for ArrayType and TabularType
    // [JF] TODO: clone values so that they cannot be altered,
    // [JF] TODO: if we decide to support LegalValues as an array itself.
    // [JF] As of today (oct 2000) it is not supported so
    // legalValues is null for arrays. Nothing to do.

    // Returns our legalValues Set (set was constructed unmodifiable)
    return (legalValues);
  }

  /**
   * Returns the minimal value for the parameter described by this
   * {@code OpenMBeanParameterInfoSupport} instance, if specified,
   * or {@code null} otherwise.
   */
  public Comparable<?> getMinValue() {

    // Note: only comparable values have a minValue, so that's not
    // the case of arrays and tabulars (always null).

    return minValue;
  }

  /**
   * Returns the maximal value for the parameter described by this
   * {@code OpenMBeanParameterInfoSupport} instance, if specified,
   * or {@code null} otherwise.
   */
  public Comparable<?> getMaxValue() {

    // Note: only comparable values have a maxValue, so that's not
    // the case of arrays and tabulars (always null).

    return maxValue;
  }

  /**
   * Returns {@code true} if this {@code
   * OpenMBeanParameterInfoSupport} instance specifies a non-null
   * default value for the described parameter, {@code false}
   * otherwise.
   */
  public boolean hasDefaultValue() {

    return (defaultValue != null);
  }

  /**
   * Returns {@code true} if this {@code
   * OpenMBeanParameterInfoSupport} instance specifies a non-null
   * set of legal values for the described parameter, {@code false}
   * otherwise.
   */
  public boolean hasLegalValues() {

    return (legalValues != null);
  }

  /**
   * Returns {@code true} if this {@code
   * OpenMBeanParameterInfoSupport} instance specifies a non-null
   * minimal value for the described parameter, {@code false}
   * otherwise.
   */
  public boolean hasMinValue() {

    return (minValue != null);
  }

  /**
   * Returns {@code true} if this {@code
   * OpenMBeanParameterInfoSupport} instance specifies a non-null
   * maximal value for the described parameter, {@code false}
   * otherwise.
   */
  public boolean hasMaxValue() {

    return (maxValue != null);
  }


  /**
   * Tests whether {@code obj} is a valid value for the parameter
   * described by this {@code OpenMBeanParameterInfo} instance.
   *
   * @param obj the object to be tested.
   * @return {@code true} if {@code obj} is a valid value for the parameter described by this {@code
   * OpenMBeanParameterInfo} instance, {@code false} otherwise.
   */
  public boolean isValue(Object obj) {
    return OpenMBeanAttributeInfoSupport.isValue(this, obj);
    // compiler bug? should be able to omit class name here
    // also below in toString and hashCode
  }


    /* ***  Commodity methods from java.lang.Object  *** */


  /**
   * <p>Compares the specified {@code obj} parameter with this {@code
   * OpenMBeanParameterInfoSupport} instance for equality.</p>
   *
   * <p>Returns {@code true} if and only if all of the following
   * statements are true:
   *
   * <ul>
   * <li>{@code obj} is non null,</li>
   * <li>{@code obj} also implements the {@code OpenMBeanParameterInfo}
   * interface,</li>
   * <li>their names are equal</li>
   * <li>their open types are equal</li>
   * <li>their default, min, max and legal values are equal.</li>
   * </ul>
   * This ensures that this {@code equals} method works properly for
   * {@code obj} parameters which are different implementations of
   * the {@code OpenMBeanParameterInfo} interface.
   *
   * <p>If {@code obj} also implements {@link DescriptorRead}, then its
   * {@link DescriptorRead#getDescriptor() getDescriptor()} method must
   * also return the same value as for this object.</p>
   *
   * @param obj the object to be compared for equality with this {@code
   * OpenMBeanParameterInfoSupport} instance.
   * @return {@code true} if the specified object is equal to this {@code
   * OpenMBeanParameterInfoSupport} instance.
   */
  public boolean equals(Object obj) {
    if (!(obj instanceof OpenMBeanParameterInfo)) {
      return false;
    }

    OpenMBeanParameterInfo other = (OpenMBeanParameterInfo) obj;

    return equal(this, other);
  }

  /**
   * <p>Returns the hash code value for this {@code
   * OpenMBeanParameterInfoSupport} instance.</p>
   *
   * <p>The hash code of an {@code OpenMBeanParameterInfoSupport}
   * instance is the sum of the hash codes of all elements of
   * information used in {@code equals} comparisons (ie: its name,
   * its <i>open type</i>, its default, min, max and legal
   * values, and its Descriptor).
   *
   * <p>This ensures that {@code t1.equals(t2)} implies that {@code
   * t1.hashCode()==t2.hashCode()} for any two {@code
   * OpenMBeanParameterInfoSupport} instances {@code t1} and {@code
   * t2}, as required by the general contract of the method {@link
   * Object#hashCode() Object.hashCode()}.
   *
   * <p>However, note that another instance of a class implementing
   * the {@code OpenMBeanParameterInfo} interface may be equal to
   * this {@code OpenMBeanParameterInfoSupport} instance as defined
   * by {@link #equals(java.lang.Object)}, but may have a different
   * hash code if it is calculated differently.
   *
   * <p>As {@code OpenMBeanParameterInfoSupport} instances are
   * immutable, the hash code for this instance is calculated once,
   * on the first call to {@code hashCode}, and then the same value
   * is returned for subsequent calls.
   *
   * @return the hash code value for this {@code OpenMBeanParameterInfoSupport} instance
   */
  public int hashCode() {

    // Calculate the hash code value if it has not yet been done
    // (ie 1st call to hashCode())
    //
    if (myHashCode == null) {
      myHashCode = OpenMBeanAttributeInfoSupport.hashCode(this);
    }

    // return always the same hash code for this instance (immutable)
    //
    return myHashCode.intValue();
  }

  /**
   * Returns a string representation of this
   * {@code OpenMBeanParameterInfoSupport} instance.
   * <p>
   * The string representation consists of the name of this class (i.e.
   * {@code javax.management.openmbean.OpenMBeanParameterInfoSupport}),
   * the string representation of the name and open type of the described
   * parameter, the string representation of its default, min, max and legal
   * values and the string representation of its descriptor.
   * <p>
   * As {@code OpenMBeanParameterInfoSupport} instances are immutable,
   * the string representation for this instance is calculated once,
   * on the first call to {@code toString}, and then the same value
   * is returned for subsequent calls.
   *
   * @return a string representation of this {@code OpenMBeanParameterInfoSupport} instance.
   */
  public String toString() {

    // Calculate the string value if it has not yet been done (ie
    // 1st call to toString())
    //
    if (myToString == null) {
      myToString = OpenMBeanAttributeInfoSupport.toString(this);
    }

    // return always the same string representation for this
    // instance (immutable)
    //
    return myToString;
  }

}
